1. Field of the Invention
The present invention relates to devices for sensing the relative position between such a device and an external surface, through the use of contacting probes which extend from the device to the surface.
2. Prior Art
This invention is an improvement over that disclosed in, for example, my prior co-pending application Ser. No. 152,220 filed May 22, 1980 now U.S. Pat. No. 4,328,621, issued May 11, 1982, which is assigned to the same assignee as the present invention. These devices generally provide a means for sensing the relative position of the device with respect to an external surface so as to provide an indication of the relative perpendicularity or angularity of the device with respect to that surface. Additional features of these devices include the ability to indicate the distance from the device to the external surface and the ability to indicate an exact position of a discontinuity in the surface, such as a hole. All of these functions are particularly useful in "teaching" industrial robots which are capable of remembering a location of a position in space once the robot has been moved to that location. Obviously, many of the various features of these devices are useful in many other industries also.
Prior to my developemnt of these devices, it was a common practice to teach such industrial robots by bringing the robot arm into approximate alignment with the surface, through visual observations and utilizing the driving mechanism of the robot. This is a very tedious operation requiring considerable labor and skill and was thus uneconomical for most applications.